Python Standard Library

Master the tools.
Solve anything.

Fluency with itertools, collections, andfunctools makes you faster as a Python developer.

Start Practicing

150 exercises · 6 levels · no account needed

A practice bridge

Learn when to reach for Python’s best tools

Python Ladder is a free curriculum for people who know the basics and want more deliberate Python practice. Its 150 exercises run directly in your browser and build fluency with the standard library and idiomatic Python.

The short challenges are useful for coding interviews and OAs, LeetCode-style problem solving, and the everyday decisions that make Python development clearer and faster.

Level 01

Core Python

Fluency with the transformations that appear everywhere.

strings · lists · tuples · dicts · sets · sorting

Start Level 1: Core Python

Level 02

Built-ins

Everyday helpers, automatic under OA pressure.

enumerate · zip · map · filter · any · all

Start Level 2: Built-ins

Level 03

Collections

Reach for the right container instead of rebuilding one.

Counter · defaultdict · deque · namedtuple

Start Level 3: Collections

Level 04

Itertools

Combinatorics, grouping, and lazy sequences.

product · combinations · chain · groupby · accumulate

Start Level 4: Itertools

Level 05

Algorithms

Battle-tested modules for high-leverage solutions.

heapq · bisect · functools · operator

Start Level 5: Algorithms

Level 06

Professional

Production-minded tools and a final mock OA.

pathlib · typing · dataclasses · re · datetime · contextlib

Start Level 6: Professional